Central Integration of Pain (NeuroPain) Lab -Lyon Neuroscience Research Center, INSERM U1028, CNRS, UMR5292, Université Claude Bernard, Bron F-69677, France; Hospices Civils de Lyon, Neurological Hospital, Centre d'évaluation et traitement de la Douleur (CETD).
Central Integration of Pain (NeuroPain) Lab -Lyon Neuroscience Research Center, INSERM U1028, CNRS, UMR5292, Université Claude Bernard, Bron F-69677, France.
Neurophysiol Clin. 2022 Nov;52(6):436-445. doi: 10.1016/j.neucli.2022.10.002. Epub 2022 Oct 26.
Pain is a private experience, whose assessment relies on subjective self-reporting. Inaccurate communication renders pain evaluation unreliable in individuals with alteration of consciousness, lack of verbal interaction, cognitive dysfunction or simple malingering, hence the importance of developing reliable objective assessment tools.
Since pain is associated with autonomic arousal, here we used readouts of autonomic activity to assess objectively the arousing effect of somatic stimuli in a human model of hyperalgesia.
We used topical capsaicin to induce cutaneous hypersensitivity in the right arm of 20 healthy volunteers, and recorded sympathetic skin responses (SSR) and numerical perceptive ratings (NRS) to stimulation of the sensitized region and its homologous contralateral site, using brush (Aβ), pinprick (Aδ) and laser (C-Warmth) stimuli.
Both subjective ratings and SSRs were significantly enhanced to stimulation of the sensitized region, and their respective ratios of maximal enhancement were positively correlated. At individual level, a significant association was observed between SSR and NRS behavior (χ2(1)= 11.03; p < 0.001), with a positive predictive value of 87% (CI95 [77-97%]) for SSR increase predicting enhancement of subjective reports. A "lie experiment" asking subjects to simulate elevated NRS failed to enhance SSRs. Significant habituation of SSRs appeared when stimuli were repeated at ∼15s intervals, hence decreasing their negative predictive value when several consecutive stimuli were averaged (NPV=46%; CI95 [30-62%]).
The SSR may represent a rapid and reliable procedure to assess cutaneous hypersensitivity, simple to use in clinical practice and resistant to simulation. Rapid habituation is a drawback that can be countered by using few repetitions and low stimulus rates.
疼痛是一种主观体验，其评估依赖于主观的自我报告。在意识改变、缺乏言语交流、认知功能障碍或单纯装病的个体中，不准确的沟通会使疼痛评估变得不可靠，因此开发可靠的客观评估工具非常重要。
由于疼痛与自主唤醒有关，因此我们使用自主活动的读数来客观评估躯体刺激在痛觉过敏的人体模型中引起的唤醒效应。
我们使用局部辣椒素来诱导 20 名健康志愿者右前臂的皮肤过敏，并记录对敏化区域及其同源对侧部位的刺激的交感皮肤反应（SSR）和数字感知评分（NRS），使用刷子（Aβ）、针刺（Aδ）和激光（C-温暖）刺激。
主观评分和 SSR 对敏化区域的刺激均显著增强，其最大增强的各自比值呈正相关。在个体水平上，观察到 SSR 和 NRS 行为之间存在显著关联（χ2(1)=11.03;p<0.001），SSR 增加预测主观报告增强的阳性预测值为 87%（CI95[77-97%]）。一项要求受试者模拟升高的 NRS 的“说谎实验”未能增强 SSR。当刺激在约 15 秒的间隔内重复时，SSR 出现明显的习惯化，因此当平均几个连续刺激时，其阴性预测值降低（NPV=46%；CI95[30-62%]）。
SSR 可能代表一种快速可靠的评估皮肤过敏的程序，在临床实践中简单易用，并且不易被模拟。快速习惯化是一个缺点，可以通过使用较少的重复和较低的刺激率来克服。
